Among olefin compounds where a part or all of hydrogen atoms are substituted with fluorine atoms, that is, fluorine-containing olefins, some industrially-useful compounds are known. For example, 1,1,2-trifluoro-2-substituted olefins such as 1,1,2-trifluorostyrene are compounds useful as organic synthetic building blocks, monomers for polymerization, materials for polymer electrolytes, and the like, and 1,1-difluoro-2,2-disubstituted olefins are compounds useful as materials for medicines such as enzyme inhibitors, for ferroelectric materials and the like. However, no method for simply and efficiently producing these compounds has been established yet. For example, Non-Patent Document 1 reports production of 1,1-difluoro-2,2-disubstituted olefins through Wittig reaction of carbonyl compounds (difluoromethylidenation). However, in the case where the carbonyl compound is a ketone, the yield is low even if an excessive amount (4 to 5 equivalents or more) of Wittig reagent is used, and further, as a phosphorus compound, a carcinogenic hexamethylphosphorous triamide must be used.
Consequently, if other fluorine-containing olefins (e.g., 1,1-difluoro-2,2-disubstituted olefins, etc.) could be simply and efficiently produced from industrially-easily-available fluorine-containing olefins such as tetrafluoroethylene or hexafluoropropylene, the method could be an extremely useful synthesis method as compared with already-existing methods.
On the other hand, olefin metathesis reaction that is a double bond recombination reaction with a metal catalyst (hereinafter this may be simply referred to as “olefin metathesis”) is widely utilized as a production method for olefins having various types of substituents. However, electron-deficient olefins having an electron-withdrawing substituent have low reactivity, and therefore use thereof in olefin metathesis is not easy. For example, Non-Patent Document 2 investigates the reactivity of olefins having various substituents and describes that the reactivity of electron-deficient olefins is low. In fact, olefins having a halogen such as a fluorine atom or a chlorine atom are electron-deficient olefins, and therefore there are few reports using them in olefin metathesis. For example, in Non-Patent Document 3, olefin metathesis of a ruthenium complex and vinylidene fluoride (i.e., 1,1-difluoroethylene) is investigated, but the report describes that the expected products, that is, ethylene and tetrafluoroethylene could not be obtained at all. In that manner, use of halogen atom-containing olefins in olefin metathesis is not practicable. Above all, tetrafluoroethylene and hexafluoropropylene are useful compounds from the viewpoint of industrial easy availability and commercialization, however, these are not only extremely electron-deficient olefins but also difficult to handle, and therefore there has been no report relating to use thereof in olefin metathesis.